Sleep trainer



FIG. 1 is a front perspective view of a sleep trainer showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines illustrate portions of the sleep trainer that form no part of the claimed design. The broken lines form no part of the claimed design. 

CLAIM The ornamental design for a sleep trainer, as shown and described. 